PSI - Issue 42

6

Author name / Structural Integrity Procedia 00 (2019) 000 – 000

Erik Calvo-García et al. / Procedia Structural Integrity 42 (2022) 251–258

256

Figure 6 – Different representative fracture patterns of reference annealed glass (left) and laser blasted annealed glass specimens (right).

The representative fracture patterns of the beveled specimens after four-point bending tests are shown in the Fig. 6. It is observed that similar patterns are obtained for reference glasses and laser blasted glasses. The failure mechanism involves the growth o cracks from the two loading points limiting the central zone of maximum bending moment, in coexistence of cracks growing form other points of the edge within the central zone. The cracks origin locations are in agreement to the predicted distribution of crack origin in glass plates subjected to four-point bending by Yankelevsky and Packer (2021). The Fig. 7 show the cumulative failure probability under bending conditions for the reference and laser blasted glasses. The obtained rupture stress values for the as received annealed and heat strengthened glass are similar to the values reported in the literature 24 . The observed bending strength distributions of the laser blasted specimens reveal a characteristic bending strength reduction, more evident for the annealed glass than for the heat strengthened glass. A reduction between the 35 and 25 % of the reference characteristic strength values are computed. In addition, it can be highlighted that the failure cumulative probability after laser blasting becomes narrower, with higher shape parameter. Thus, the minimum expected strength, employed for structural glass element design, results mainly preserved after the laser surface treatment.